Respirator systems protect the user from particles, gases and/or vapors, which may compromise the quality of the breathing air and be hazardous to health. A respirator system has at least one filter for filtering air and a breathing mask, to which the filtered air is fed. The breathing mask may be a hood, a helmet, a visor or even an oronasal mask or half mask.
To provide especially reliable protection from contaminated air, blower-assisted respirator systems additionally have a blower unit, which has a blower and a motor for driving the blower. The blower unit draws in the air filtered through the filter and generates discharged air, which is fed to the breathing mask. The blower unit is operated such that an overpressure prevails in the breathing mask, so that only filtered air can escape from the filter mask, but no contaminated air can enter the interior of the breathing mask. Respirator systems with a blower filter device assist the user by lowering the airway resistance, unlike conventional gas masks, and this make fatigue-free long-term use possible.
Blower-assisted respirator systems, which are also called “PAPR” (Powered Air-Purifying Respirator) systems, are known, for example, from DE 100 21 581 B4, EP 0 413 555 A1, and DE 689 09 707 T2.
It is decisive, for the breathing protection offered by a blow-assisted respirator system, to rule out reduced pressure in the breathing mask during the inhalation phase, which is achieved by feeding a defined, constant volume flow of filtered air into the breathing mask. It is thus ensured that the inhaled air is supplied exclusively through the feed of air from the blower filter device rather than from the contaminated surrounding area due to possible leaks of the breathing mask, because excess air is steadily flowing through the exhalation valve of the breathing mask into the surrounding area.
It is known that parameters of the respirator system itself and parameters of the surrounding area, in which the respirator system is operated, are taken into account in the mode of operation of the motor of the blower unit in order to make a constant volume flow of filtered air available to the user of the respirator system.
Methods for operating blower-assisted respirator systems are disclosed, for example, in DE 10 2010 031 754 B4, DE 10 2004 013 453 B4, US 2009/0 266 361 A1, WO 2011/019 778 A1, and DE 102 50 414 A1. For example, WO 2011/019 778 A1 thus shows a method for regulating a motor-operated blower-respirator system for supplying a uniform volume flow, where the density of the ambient air or an ambient temperature and an ambient pressure are taken into account for setting a manipulated electric variable of the motor on the basis of two calibration values.